Distortion control for high temperature heat exchangers



R. STOCKMAN June 8, 1965 DISTORTION CONTROL FOR HIGH TEMPERATURE HEAT EXCHANGERS Filed June 21, 1963 illilllk United States Patent Oflice 3,l87,84 Patented June 8, 1965 3,187,804 DESTORTTON CONTROL FOR HIGH TEMPERA- TUBE I-EAT EXCHANGERS Richard Stockman, Friendship, N.Y., assignor to Combustion Engineering, Inc., New York, N.Y., a corporation of Delaware 7 Filed June 21, 1963, Ser. No. 289,568 4 Claims. (Cl. 165-7) The present invention relates to improvements in regenerative heat exchange apparatus of the rotary type, and particularly to a novel arrangement adapted and arranged to permit independent parts of such apparatus to have freedom of radial and axial expansion, and moreover utilize variations of expansion to minimize fluid leakage between independent parts of the apparatus.

Conventional heat exchange apparatus of this type includes a cylindrical rotor carrying a mass of heat absorbent plates that are rotated alternately between ducts carrying a heating fluid and a fluid to be heated in order that heat from one fluid may be transferred to the other through the intermediary of the heat absorbent plates. The rotor is enclosed in a housing to which the ducts carrying the heating fluid and the fluid to be heated are connected, and the housing is in turn provided with apertured end plates which direct the several fluids through the enclosed rotor. To preclude fluid leakage between fixed and movable parts of the rotor, suitable sealing means must be provided around the ends of the rotor and at other predetermined locations. All such sealing means tend to minimize the clearance spaces between the rotor and housing, and to permit free turning of the ,rotor, certain minimum clearance spaces should be maintained at all times. Inasmuch as heat exchange apparatus of this type is subjected to a complex assortment of thermal and structural forces, it has been considered virtually impossible to isolate the various forces in order that distortion may be controlled and an ideal sealing relationship may be maintained at all times. Consequently, while certain types of deflection have been accommodated or controlled, others remain substantially uncontrolled and fluid leakage in heat exchange apparatus, especially that which is adapted for high temperature application, remains as a serious problem.

Therefore, the principal object of this invention is to provide an arrangement that isolates and accommodates various thermal forces in order that an improved sealing relationship between independent parts of the heat exchanger may be achieved.

A further object of the present invention is to provide a rotor arrangement that is suitable for use at higher temperatures ranging upward up to the thermal limitation of the rotor.

A still further object of the present invention is to provide a heat exchanger arrangement that effectively isolates high temperature zones from low temperature zones in order that expensive temperature resistant materials are not essential for all parts of the rotor and rotor support structure.

These and other objects of the invention will become more apparent when read in conjunction with the accompanying drawings in which:

FIGURE 1 is a sectional elevational view of a rotary regenerative heat exchanger constructed in accordance with the present invention.

FIGURE 2 is an enlarged sectional view of the rotor post and linkage assembly.

FIGURE 3 is a cross sectional View of the rotor post showing radial guide means and rocker assemblies.

In FIGURE 1 of the drawing the numeral 10 designates a rotor having an outer cylindrical shell 12 and an inner cylindrical shell 14 joined by radial partitions to form a series of substantially sector shaped compartments that carry a mass of heat absorbent material alternately between a heating fluid and a fluid to be heated. The

rotor is carried by a rotor post 18 which is in turn mount ed on a support bearing 22 at one end and. guided against lateral displacement at its other end by a guide bearing 24. The rotor is surrounded by a housing 26 having end plates 28 at opposite ends thereof apertured at 32 and 34 and adapted to be connected to suitable inlet and outlet ducts 35 and 37 for the heating fluid and other ducts 41 and 43 for the fluid to be heated.

In accordance with the invention, an annular space 36 lying between the rotor post 18 and the inner rotor shell 14 is arranged to provide a heat barrier that substantially precludes the conduction of heat from the rotor to the rotor post.

that are mounted on the rotor post 18 and arranged to extend radially outward therefrom into a spaced relation with the inner rotor shell 14. An annular flange.

42 secured to the inner periphery of rotor shell 14 is adapted to carry a rocker pad 44 in axial alignment with each support member 38. The rocker pads 44 are comprised of blocks of a relatively hard metal which serve as stiflening means for parts of the annular flange 42 which lie in contacting arrangement with the linkage arms 46 carried by the support members 38. The arms 46 are pivotally attached to the members 38 by means such as pins 48 to permit freedom of movement about their axis of rotation. Each linkage arm 46 is formed with an arcuate surface 52 whose center of rotation is the opening at the opposite end of linkage arm 46 through which the pin means 48 is directed. When the pivot members or linkage arms 46 are disposed in an essentially vertical position directly abutting the rocker pads 44, relative radial expansion between the rotor and the rotor post will be accommodated by a simple shifting of the linkage arm about its axis of rotation.

The exact position at which the support members 38 and linkage arms 46 are located with respect to axially spaced ends of the rotor is dependent upon the various materials being utilized for the rotor post and the rotor shells, and upon the temperature change to be encountered by each part of the rotor under normal conditions of operation.

Thus, for example, in an arrangement suitable for conditions in which the gas temperature will approach 1500 F. the rotor post may be constructed of low cost carbon steel while the rotor proper including inner and outer rotor shells is comprised of heat resistant stainless steel. Since the rotor operates in a high temperature zone While the rotor post operates in a relatively cool zone, and since these members will be comprised of materials having different coeflicients of expansion, the axial as well as the radial expansion of the rotor shells and the rotor post will differ substantially. However, by proper design, the expansion w downward and away from the support bearing 22 may be balanced against the expansion x of the rotor in the opposite direction to obtain an operating condition whereby the upper edge of the rotor will lie in sealing relation with its adjacent end plate during normal operating conditions. Inasmuch as expansion of the rotor y is in the same axial direction as the expansion w of the rotor post, the position of the lower edge of the rotor at operating temperature will depend upon the sum of the rotor post expansion w and the directionally similar rotor expansion y, and the cold setting of the rotor may be made accordingly.

Thus an optimum position for the annular flange 42 to support the rotor would be such that it would lie in- In addition the annular space 36 I houses a number of evenly spaced support members 33 termediate ends of the rotor at a location where axial expansion of the rotor due to its being heated through a normal temperature use would move axially remote ends of the rotor in opposite directions an amount calculated to provide a preferred sealing relationship with the end plates 28 at opposite ends of the rotor housing 26. r

In order that the heat of the fluids flowing through the rotor may be further isolated from the rotor post 18,'a layer of insulation 54 is applied to the inner surface of the inner rotor shell 14. By placing the insulation layer on the inner surface of shell 14, the rotor shells 12 and 14 and their intervening rotor structure are subjected to substantially the same thermal conditions so that they expand in a similar direction and at a similar rate. At the same time, heat from the rotor is precluded from reaching the annular chamber 36.and the rotor post 18 by the layer of insulation 54 on the inner rotor shell 14.

Radial. guide members 56- at opposite ends of the rotor are secured to the rotor post adjacent ends of the support members 38 and adapted to extend outward into a sliding contact with slot means 58 carried by the inner rotor shell. This arrangement precludes relative rotational movement between the rotor post and rotor shell assembly while it simultaneously permits a limited amount of relative radial expansion and contraction such as. may be permitted by the pivotal linkage means While this invention has been described with reference to the embodiment illustrated in the drawing, it is evident that numerous changes may be made without departing from the spirit of the invention and it is in-' tended that all matter contained in the above description or shown in the accompanying drawings shall be inter preted as illustrative and not in a limiting sense.

I claim:

1. Rotary regenerative heat exchange apparatus having a rotor including a central rotor post, inner and outer rotor shells concentrically spaced from the rotor post,

radial members extending between inner and outer rotor l shells to provide a series of sectorial compartments therebetween a mass of heat absorbent material carried in the compartments of the rotor, a cylindrical housing surrounding the rotor including end plates at opposite ends thereof having apertures that direct the flow of a heating fluid and a fluid'to be heated through the compartments of the rotor, bearing means rotatably supporting the rotor post for rotation about its central axis, support means extending outward from the rotor post into spaced relation with the inner rotor shell, linkage means pivotally linking the inner rotor shell and said support means, and radial guide vanes extending radially between the inner rotor shell and the rotor post adapted to preclude relative rotational movement between the rotor post and the surrounding rotor shells.

2. Rotary regenerative heat exchange apparatus as defined in claim 1 wherein the radial guide vanes carried by the rotor post slidably engage the inner rotor shell to preclude relative rotary movement While permitting relative radial movement therebetween.

3. Rotary regenerative heat exchange apparatus as defined in claim 2 wherein the pivotal linkage means lies intermediate axially displaced radial guide vanes.

4. Rotary regenerative heat exchange apparatus as defined in claim 1 wherein the means pivotally linking the inner rotor shell to said support means is positioned between axially spaced ends of the rotor at a point Wherein axial movement of thevrotor postvdue to its thermal expansion substantially negates the thermal expansion of the rotor in the opposite direction whereby the position of the adjacent end of the rotor will not change throughout wide variations of temperature;

References Cited by the Examiner UNITED STATES PATENTS 2,744,731 5/56 Brandt 165-9 3 ,072,182 1/ 63 Persson l65'-9 FOREIGN PATENTS 685,702 l/ 5 3 Great Britain.

CHARLES SUKALO, Primary Examiner. 

1. ROTARY REGENERATIVE HEAT EXCHANGE APPARATUS HAVING A ROTOR INCLUDING ROTOR POST, INNER AND OUTER ROTOR SHELLS CONCENTRICALLY SPACED FROM THE ROTOR POST, RADIAL MEMBERS EXTENDING BETWEEN INNER AND OUTER ROTOR SHELLS TO PROVIDE A SERIES OF SECTIONAL COMPARTMENTS THEREBTWEEN A MASS OF HEAT ABSORBENT MATERIAL CARRIED IN THE COMPARTMENTS OF THE ROTOR, A CYLINDRICAL HOUSING SURROUNDING THE ROTOR INCLUDING END PLATES AT OPPOSITE ENDS THEREOF HAVING APERTURES THAT DIRECT THE FLOW OF A HEATING FLUID AND A FLUID TO BE HEATED THROUGH THE COMPARTMENTS OF THE ROTOR, BEARING MEANS ROTATABLY SUPPORT- 